The primary difference between the 2.4 GHz and 5GHz wireless frequencies is range as the 2.4GHz frequency is able to reach farther than the 5GHz frequency. This is a result of the basic characteristics that waves attenuate much faster at higher frequencies.
The second difference is the number of devices on the frequencies. 2.4GHz suffers more interference than 5GHz.
(1) The older 11g standard only uses the 2.4GHz frequency, majority of the world is on it. 2.4 GHz has fewer channel options with only three of them non-overlapping, while 5GHz has 23 non-overlapping channels.
(2) A lot of other devices are also on the 2.4 GHz frequencies, the biggest offenders are microwaves and cordless phones. These devices add noise to the medium that can further decrease the speed of wireless networks.
The third difference is that the 5Ghz WiFi can deliver a higher WiFi speed than 2.4Ghz WiFi.
If there is too much interference around and your clients support 5GHz, it’s recommended to use 5GHz wireless network, otherwise you can select 2.4GHz.